Power Supply for ESD Systems

[Electrifier]

Dears,

Can you please give me the information about preferred power supply for Emergency shut down systems i.e. AC supply from UPS or DC supply with battery backup. What is the preferred state of input loops i.e. open loop or closed loop.
If there is any site containing information about this, please mention.

 

[dpc]

I think this will vary depending on the industry and type of system being protected.

Can you give us some additional info on your application?

dpc

 

[Electrifier]

The system is suppose to be used at oil&Gas exploration unit. System is used to shutdowm the Generators, engine driven compressors, pumps, ESV's of Seperators and vessels in case of any emergency.
ESD System is suppose to be activated by Hand operated Emergency push button stations and process securities( High level and pressure switches of tanks and vessels.

 

[dpc]

For a system like this that will be suject to a lot of hard knocks, my first thought would be to use a "fail-safe" de-energize-to-trip system. This could include undervoltage release coils on any stored-energy circuit breakers.

The Emergency stop pushbuttons would be normally-closed, opening when actuated and probably manually reset.

For the level and pressure switches you can use a two out of three logic if you're worried about nuisance tripping.

This type of system will provide protection against broken wires, loose terminations, loss of control power, etc.

But I'm not burdened by a lot of actual knowledge about these units, so take this with a grain of salt.

dpc

 

[Electrifier]

Thanks, DPC. All information is valuable and seems to be best practicable. What do you think about power supply, AC from UPS or DC with battery backup? Is there any web site containing information in this concern

 

[dpc]

With a de-energize to trip system, the power supply can be ac. But since you will likely have black-start capability, you will probably have a dc battery system anyway, so it could be used.

For a fail-safe system using continuously energized relay coils, I would avoid dc control power. My experience has been that the dc relays suffer coil failures much more frequently than ac coils.

You might consider an inverter system to provide ac control power from your battery system. This could include a static switch to tranfer ac control power to line power in the event the inverter failed, or you can use two hot-swapping inverters.

dpc